Returning to Electronics (As a Hobby) After 10-12 Years...

[KG7AMV]

It has been 10-12 or so years since I had worked as an EE. I switched careers and became a Pilot I never really looked back except for the occasional simple home electronics repair! Nothing requiring to much knowledge or engineering most the stuff is throwaway now days so cheaper to replace then purchase a component.

I have to say being out of it for so long wow things have moved leaps and bounds over the years!

So what has me returning? Hobby Reasons!

Back Story,

I got a Second hand CNC lathe and it has a Microkinetics Controller that has a Failure on one of the inputs software says unexpected limit swith closure on M2- limit switch. Contacted the company!! Yep! The company wants $300.00 for a new board ouch or $150.00 to see if they can repair it. They have no real tech support or documents on the unit unless you want to give them $150.00 for engineering service Ouch! A schematic would be helpful but not really needed. So this brings me to where I am at right now dusting off my tools from years of storage!

To me it is not worth $150.00 to have it repaired or 300.00 for a new one! As a new breakout board that will allow me to run full featured software LinuxCNC or Mach3 is a fraction of the cost. Their software Turnmaster Pro is rather limited with functions would be nice if they allowed you to select what axis uses what motor just in case a controller has an issue you could switch it to talk to another move a cable and have the machine running in a matter of min vs having it down for weeks on end waiting for repair or replacement parts. 

From the message the error seems to be on the M2- Limit Switch Input.

So I traced the M2- limit circuit down. The m2- limit pin goes from the HD50 thru RP5 on pin 15 out Pin 3 thru an opto coupler U21 pin 4 outputs pin 14 thru RP4 to the Xilinx XC95108.

The passive components RP4,5, and the Optocoupler seem to be working as they should. When power is on the pin on the XC95108 is at 5V high when I hook up a limit switch and trip it the pin goes Low to ground as it should.  I cross checked it with a known working circuit M1- Limit. So next step I guess since I No longer have a scope or logic analyzers so I have to use the tools I have.

I May have to see if Tektronix's local to me still has an outlet store for some low cost used equipment.

I will hook up a jtag possibly this weekend and see if I can toggle the pin on the xilinx to active high or see if it is low or figure out if something else is not working on the board causing it to go active low state in another circuit.

The Modern Jtag debugging software looks wonderful and simple to use and I cannot wait to give it a try. My friend another EE has been using topjatag for debugging and also said to try gojtag which is an open source debugging software but he said he has had limited use of it but should have some useful functions.

Anyone use gojtag software? Or recommend another software? 

Photo of the board I am diagnosing is attached.

Info on the board can be found at Microkinetics MN400 http://www.microkinetics.com/index.php?page=mn400

Glad to be a member of the forum and enjoy reading and learning of the technology a wealth of information! I have missed out on a lot over the years!

This project for sure brush off the rust from my skills it will be fun and educational for sure!   


Thanks.


 

[jlmoon]

Welcome back from a fellow EEV'r

[KG7AMV]

Yea, going to be fun for sure. Did get a request today to Ferry a plane to Nigeria! Ummm nope no Ebola for me! 

[JoeO]

Yea, going to be fun for sure. Did get a request today to Ferry a plane to Nigeria! Ummm nope no Ebola for me!

Just curious:  Is that a typical request for you or is that a rare job offer because of the Ebola in Africa.

[KG7AMV]

Yea, going to be fun for sure. Did get a request today to Ferry a plane to Nigeria! Ummm nope no Ebola for me!

Just curious:  Is that a typical request for you or is that a rare job offer because of the Ebola in Africa.

100% Normal Request. It's what I do for a Living! Just avoiding that part of the world right now!

[robrenz]

Welcome to the forum!  Just a warning, I did a similar return several years ago and it can be very, very, very expensive

[Howardlong]

Yea, going to be fun for sure. Did get a request today to Ferry a plane to Nigeria! Ummm nope no Ebola for me!

Just curious:  Is that a typical request for you or is that a rare job offer because of the Ebola in Africa.

100% Normal Request. It's what I do for a Living! Just avoiding that part of the world right now!

You're not on Dangerous Flights are you? ;-)

If you're flying singles over the ocean I think you must be nuts! I have a Cherokee and taking that over the English Channel is more than enough adrenaline for me, thank you, but at least there are plenty of boats around to land next to if the donkey quits.

Welcome back to EE.

[tggzzz]

I have to say being out of it for so long wow things have moved leaps and bounds over the years!

Being in the process of doing the same, my opinion is that in someways it has changed significantly, in some ways it has changed very little. That implies you won't have too much difficulty getting back into the swing of things. Just use the same techniques you used when starting, and you'll pick up the changes in no time at all.

The major change is that things tend to smaller and/or cheaper and/or faster - which is great for the hobbyist.

So what hasn't changed?

• design and debugging - you'll use the same metality and techniques
• microcomputer systems, except that a $5 single chip has replaced a couple of eurocards, and that an in-circuit emulator or debugger costs $50
• programming MCUs and their peripherals has changed very little, but there are free simple (and complex) programming environments
• test equipment is largely unchanged, except that small digital oscilloscopes (some with questionable firmware) have taken the place of larger analogue scopes.
• peripherals are still ADCs, DACs, stepper motors, LEDs
• analogue is still the same old analogue, but the frequencies have moved higher towards RF

And the smaller but important changes include:

• easy to make single and double-sided PCBs, either using the toner-transfer method or getting a PCB house to fab it remarkably cheaply and fast. Multilayer PCBs are also well within the scope of amateurs
• small pitch and surface mount devices, which are surprisingly easy to use at home with a very small amount of equipment - don't be afraid of them
• the rise of robotics, which is a great fun - especially for kids (of all ages)
• the maker movement, particularly with very easy to use (albeit limited) development environments
• CPLDs still exist, but FPGAs are now more interesting and practical for many purposes
• a bewildering range of very similar components, but most are recognisable from before
• software defined radios
• networking, particularly wireless and IoT
• the web and self-publishing, so there are many tutorials at your fingertips. Nowadays the key skill is not finding information, it is speedily deciding what to ignore

[SeanB]

Don't worry, Nigeria has said it is Ebola free. I would be more worried about other things than that, it is not really a worry.

[KG7AMV]

What I fly i would have to land in at least 1 Ebola zones for fuel/rest.